NC0044423_Modification_20210719

July 7, 2021
NPDES Wastewater Program
Department of Environmental Quality
1617 Mail Service Center
Raleigh, NC 27699
AppAj�chian
UNIVERSITY
Facilities Management
ASU Box 32105
Boone, NC 28608-2105
828-262-3190
facilitiesmanagement.appstate.edu
RECEIVE®
RE: Appalachian State University NPDES Permit NCo044423 Modification Request J U L 19 2021
To Whom It May Concern: NCDEQ/DWR/NPDES
Appalachian State University (ASU) is submitting this major permit modification request and supporting
information to move the discharge outfall location. The ASU Water Treatment Plant (WTP) discharges
backwash and CIP waste to Norris Branch Reservoir under the auspices of NPDES Permit NCo044423•
The existing permit expired March 31, 2021 and ASU has applied for but has not yet received a renewed
permit. The current permit has been administratively extended. As such ASU is submitting a permit
application addendum to request a change in the discharge outfall location.
The current NPDES discharge outfall is in close proximity to the WTP's intake structure in Norris Branch
Reservoir. ASU desires to move the discharge outfall location downstream of the reservoir into Norris
Branch. The primary driver to move the outfall is to reduce impact from the discharge on the water intake.
The effluent discharge from the WTP represent waste from the treatment process — backwash and CIP
water. Discharging the waste so close to the intake results in the recycling of undesirable constituents
back into the intake for removal again. In addition, the effluent discharge disturbs the bottom of the lake,
stirring up solids and increasing the turbidity and other constituents in the WTP influent following a
discharge event. Relocating the discharge downstream of the reservoir in Norris Branch will remove the
negative impacts on the WTP intake.
ASU, DEQ, and Dewberry participated in a conference call on May 4, 2021 to discuss the potential to
move the outfall. DEQ indicated it was feasible to move the discharge location to Norris Branch. In
addition, DEQ agreed to consider allowing ASU to use existing stormwater infrastructure to convey the
discharge to Norris Branch. The DEQ requested that the application addendum include the following:
Analysis of effluent flow data to recommend a new flow rate for consideration during permitting
as the effluent flow rate has decreased with operation of the low-pressure membrane system;
A 7Q10 flow rate from USGS for the proposed new outfall location where the existing stormwater
sewer discharges to Norris Branch;
A feasibility analysis and exhibit for the re-route and tie-in of a new gravity backwash discharge
line from the backwash wet well to the existing storm sewer; and
An alternative analysis comparing two metals treatment technologies for removing metals from
the WTP effluent in lieu of moving the discharge. A secondary benefit to moving the outfall will be
potential to improve compliance with copper and zinc effluent limits. As ASU will struggle to meet
current numerical limits for copper and zinc, DEQ requested the application addendum include
A MEMBER INSTITUTION OF THE UNIVERSITY OF NORTH CAROLINA AN EQUAL OPPORTUNITY EMPLOYER
Page 1 of 4

NPDES Wastewater Program
July 7, 2021
an evaluation of metals treatment options to be considered as alternatives to moving the
discharge.
Water Treatment Plant Effluent Flow
The WTP effluent flow based on data collected July 2019 — July 2020 is presented in Table 1. We request
updated flow data in Table i be used for developing effluent limits. ASU typically does not discharge daily.
Discharges typically occur over a 2-hour period. This results in an instantaneous discharge of 150 gallons
per minute (gpm) at average flow and 400 gpm at maximum flow.
Table i. Effluent Flow Based on July 2oig — July 2o2o Data
WTP Effluent Discharge
Average Flow (gpd) 18,000
Maximum Flow (gpd) 48,000
Norris Branch 7Q10 Flow
Dewberry coordinated with USGS to develop a 7Q10 flow rate for the proposed outfall location. The
proposed outfall is where the existing stormwater sewer discharges to Norris Branch. The estimated
drainage area for the proposed discharge location (36.238o695,-81.6683120) is 0.37 square miles.
There are no USGS records or monitoring stations on Norris Branch. A nearby station on Howards Creek
was used with a ratio of the drainage areas to calculate the 7Q10 flow. USGS estimated low -flow
characteristics based on "natural -flow" conditions, as though the upstream impoundment was non-
existent. This is because the overflow is used during high -flow conditions and would not be a factor under
low -flow conditions. The annual 7Qio flow rate ranges from o.o85 to o.16 cfs, with an average and a
median about 0.12 cfs. The emails documenting the 7Qio flow information from USGS are provided in
Attachment A.
Existing Storm Sewer Evaluation
ASU desires to use existing stormwater infrastructure to convey the discharge to Norris Branch.
Dewberry verified that the existing stormwater system is not covered under a permit using the NCDEQ
Stormwater Permit Tracker Map. Dewberry performed a capacity evaluation on the existing stormwater
system for a 25-year storm event using a hydraulic modeling software. Dewberry proposed two pipeline
improvement alternatives, with opinions of probable costs ranging from $15,000 to $61,000. Both
alternatives the cost opinions are detailed in the Existing Storm Sewer Evaluation Memorandum, located
in Attachment B. Based on the evaluation of the existing storm sewer system and the proposed
improvements, the existing storm system has the capacity to carry the additional backwash discharge.
Upon approval of the new discharge outfall, ASU will select between pipeline alternatives.
Page 2 of 4

NPDES Wastewater Program
July 7, 2021
Evaluation of Metals Treatment Systems
The NCDEQ has requested the evaluation of two metals treatment alternatives for comparison to the
request to move the discharge outfall to Norris Branch. Dewberry developed a preliminary evaluation of
reverse osmosis and ion exchange. The preliminary evaluation included conceptual sizing and
development of order of magnitude costs.. The Metals Treatment Alternative Analysis is attached in
Attachment C.
Reverse Osmosis and Ion Exchange would be effective at removing copper and zinc and can achieve the
effluent limits of the existing NPDES permit. Table 2 summarizes the opinions of probable capital costs
for the treatment options and new discharge pipeline.
Table 2. Preliminary Opinions of Probable Costs
Alternative
Cost
Move Discharge Pipeline
$ 15,000- $ 61,000
Ion Exchange
$ 2,1.00,000
Reverse Osmosis
$ 4,200,000
Historical data indicates >99% of copper and >96% of zinc from the WTP intake are removed in the WTP
process and are not discharged back to Norris Branch. The copper and zinc removed are presumed to be
removed in the sludge from the existing sludge thickener. The costs of ion exchange and reverse osmosis
are very high for the minimal additional copper and zinc removal that will be provided beyond what is
already removed and not returned to the lake.
Both treatment alternatives have significantly higher capital costs than the costs associated with moving
the discharge location. In addition, the treatment alternatives will have annual operating costs, which will
be minimal for a new discharge location. The treatment alternatives also do not achieve the primary
objective which is to move the outfall downstream of the water treatment plant intake. As such, we have
determined that moving the outfall is the most effective method to achieve the primary objectives of
reducing impact of the effluent on the water intake and improving compliance with effluent copper and
zinc limits. Upon approval of the new discharge location, ASU will select an alternative for connecting to
the sewer and submit final design documentation for Authorization to Construct.
I appreciate your consideration of the permit modification request. Please feel free to contact me at
828.262.8784 with questions regarding this submittal.
Daniel Gryder
Cc: Anthony Miller, PE
Leigh -Ann Dudley, PE
Page 3 of 4

NPDES Wastewater Program
July 7, 2021
Enclosed:
Attachment A- USGS Correspondence
Attachment B- Existing Storm Sewer Evaluation
Attachment C-Metals Treatment Alternatives Analysis
Page 4 of 4

Attachment A
Russell, Jocelyn
From: Weaver, John C <[e-mail]>
Sent: Tuesday, June 15, 2021 5:34 PM _
To: Russell, Jocelyn RECEIVED
Cc: Dudley, Leigh -Ann; Albertin, Klaus P; Weaver, John C
Subject: RE: [EXTERNAL] Appalachian State University Stormwater Discharge S6Wrn As2021
Drainage Area
NCDEQ/DWR/NPDES
[CAUTION] External Email. DO NOT click links or open attachments unless expected. Please use the "Phish Alert" button to report all
suspicious emails.
Jocelyn,
In the low -flow response to you on April 6, 2021, the estimated low -flow characteristics were based on "natural -flow'
conditions as though the upstream impoundment was non-existent. Please review the information shown within the
April 6 email using red font color. As I do not have any USGS records of discharge for the points of interest, there is no
means to account for the presence of this upstream feature in the downstream low -flow characteristics. Therefore, the
provided estimates were described as being reflective of "natural -flow" conditions.
I didn't completely follow the meaning of your statement within your email saying, "From observations in the field, we
know that the ASU Lake/impoundment's overflow ties in further downstream and does not contribute to the flow at the
selected point." As the overflow is used during high -flow conditions, this would not be a factor under low -flow
conditions. Examination of Google Earth imagery does indeed appear to show the overflow channel tying back into the
stream downstream from the points of interest. But again, the low -flow estimates do not account for the presence of
the impoundment.
I completed a quick drainage -basin delineation within the USGS StreamStats application for the new location
coordinates you provided in today's email. The drainage area for this point of interest is still 0.37 sgmi, indicating no
change from the drainage area associated the point of interest for the April 6 low -flow estimates. Thus the low -flow
estimated provided via the April 6 email remain in effect.
If this still does not address your questions, please let me know.
Thank you.
Curtis Weaver
J. Curtis Weaver, Hydrologist, PE Email: icweaverOusas.aov
USGS South Atlantic Water Science Center Online: httns://www.uscs.aov/centers/sa-water
North Carolina - South Carolina - Georgia
3916 Sunset Ridge Road
Raleigh, NC 27607
Phone: [phone] // Fax: [phone]
From: Russell, Jocelyn <[e-mail]>
Sent: Tuesday, June 15, 2021 11:23 AM
To: Weaver, John C <[e-mail]>

Cc: Dudley, Leigh -Ann <[e-mail]>
Subject: [EXTERNAL) Appalachian State University Stormwater Discharge Streamstats Drainage Area
This email has been received from outside of DOI - Use caution before clicking on links, opening attachments, or responding.
Hi Curtis,
In April we inquired about the 7Q10 for a potential future wastewater discharge to be located on Norris Branch,
approximately 700 feet downstream from ASU Lake. We understand there is not flow data on Norris Branch so the 7Q10
evaluation was based on comparing the drainage area for the proposed location and the drainage area for Howards
Creek which does have flow measurement. Since then, we have been able to identify a more exact discharge location
(36.2380695,-81.6683120). The streamstat report shows that the ASU Lake/impoundment contributes to the flow in the
stream at the proposed discharge location. From observations in the field, we know that the ASU Lake/impoundment's
overflow ties in further downstream and does not contribute to the flow at the selected point. Prior to submitting an
application to NC DEQ to move our outfall to the new location, we would like to confirm the estimated 7Q10 at the
proposed discharge location. Can you help us understand if the drainage area being estimated by Streamstats is
accurate since ASU lake does not discharge through the new point of interest? We would be happy to schedule a call to
review our question if that would be helpful.
Thank you!
2

Jocelyn Russell, EIT
Staff Engineer
2610 Wycliff Road, Suite 410
Raleigh, NC 27607-3073
D 919.746.9627 C 518.353.2274
1 Dewberry
in V Co 0
www.dewberry.com
Visit Dewberry's website at www.dewberry.com If you've received this email even though it's intended for someone
else, then please delete the email, don't share its contents with others, and don't read its attachments. Thank you.

Russell, Jocelyn
From: Dudley, Leigh -Ann
Sent: Thursday, June 10, 2021 10:43 AM
To: Russell, Jocelyn
Subject: FW: USGS response to DWR USGS Low Flows request # 2021-117 (dated 2021/03/31)
for Norris Branch Watauga County ... RE: [EXTERNAL] Low -flow request approval
Leigh -Ann Dudley, PE
Associate, Project Manager
Water Market Segment
2610 Wycliff Road, Suite 410
Raleigh, NC 27607-3073
D 919.424.3764 C 919.418.1727
LICENSED PE: NC, AL
Dewberry
in V C-3— O
www.dewberry.com
From: Weaver, John C <[e-mail]>
Sent: Tuesday, April 6, 2021 11:42 AM
To: Whitmyer, Holly <[e-mail]>
Cc: Hill, David A <[e-mail]>; [e-mail]; Montebello, Michael J
<[e-mail]>; Albertin, Klaus P <[e-mail]>; Weaver, John C
<[e-mail]>
Subject: USGS response to DWR USGS Low Flows request # 2021-117 (dated 2021/03/31) for Norris Branch Watauga
County... RE: [EXTERNAL] Low -flow request approval
[CAUTION] External Email. DO NOT click links or open attachments unless expected. Please use the "Phish Alert" button to report all
suspicious emails.
Ms. Whitmyer,
In response to your inquiry about the low -flow characteristics for a location on Norris Branch approximately 700 feet
downstream from a small impoundment adjacent Howard Knob near Boone in central Watauga County, the following
information is provided:
For the record: The point of interest is located approximately 700 feet downstream from the dam for a small
impoundment (ASU Lake) located on the stream. The estimated low -flow characteristics provided below do not account
for the presence of this impoundment on the stream but rather reflect "natural flow" conditions as though the
impoundment was nonexistent.

No USGS discharge records are known to exist for the point of interest, identified by the lat/long coordinates (36.23790,
-81.66773) provided via email dated 03/31/2021 from the DWR USGS Low Flow portal following your request
submission. However, a check of the low -flow files here at the USGS South Atlantic Water Science Center (Raleigh
office) indicates previous low -flow determinations for two points of interest on Norris Branch upstream from the point
of interest (closer to the dam for the impoundment). Completed in 1968 and 1984, the low -flow characteristics were
estimated based on transfer of flow characteristics from a nearby USGS partial -record site on Howard Creek at Sands
(station id 03160310, drainage area at 10.3 sgmi).
In the absence of site -specific discharge records sufficient for a low -flow analysis, estimates of low -flow characteristics at
ungaged locations are determined by assessing a range in the low -flow yields (expressed as flow per square mile
drainage area, or cfsm) at nearby sites where estimates have previously been determined.
A basin delineation completed using the online USGS StreamStats application for North Carolina
(https://streamstats.usgs.gov/ss/) indicates the drainage area for the point of interest (StreamStats adjusted
coordinates 36.23792,-81.66773 NAD83) is 0.37 sgmi, which confirms the drainage area submitted as part of the
request information.
For streams in Watauga County, low -flow characteristics published by the USGS are provided in two reports:
(1) The first is a statewide report completed in the early 1990's. It is USGS Water -Supply Paper 2403, "Low -flow
characteristics of streams in North Carolina" (Giese and Mason, 1993). An online version of the report is available at
http://pubs.usgs.gov/wsp/2403/report.pdf. The report provides the low -flow characteristics (based on data through
1988) via regional relations and at -site values for sites with drainage basins between 1 and 400 sgmi and not considered
or known to be affected by regulation and/or diversions.
(2) The second is a statewide report published in March 2015. It is USGS Scientific Investigations Report 2015-5001,
"Low -flow characteristics and flow -duration statistics for selected USGS continuous -record streamgaging stations in
North Carolina through 2012" (Weaver, 2015). The report is available online at
http://Pubs.usgs.gov/sir/2015/5001/. The report provides updated low -flow characteristics and flow -duration statistics
for 266 active (as of 2012 water year) and discontinued streamgages across the state where a minimum of 10 climatic
years discharge records were available for flow analyses.
Low -flow characteristics estimated for point of interest:
Inspection of the two reports indicates the presence of four (4) nearby selected USGS partial -record site (4) and
continuous -record streamgages (0) in the general vicinity of the point of interest where low -flow characteristics were
published. Among these 4 sites, the low -flow discharge yields for the indicated flow statistics are as follows:
Annual 7Q10 low -flow yields =_> from 0.23 to 0.42 cfsm (average about 0.32 cfsm, median about 0.33 cfsm)
Annual 30Q2 low -flow yields =_> from 0.49 to 0.91 cfsm (average about 0.72 cfsm, median about 0.74 cfsm)
Winter 7Q10 low -flow yields =_> from 0.31 to 0.57 cfsm (average about 0.46 cfsm, median about 0.48 cfsm)
Annual 7Q2 low -flow yields ==> from 0.39 to 0.7 cfsm (average about 0.57 cfsm, median about 0.61 cfsm)
Average annual discharge yields ==> from 1.9 to 3.2 cfsm (average about 2.3 cfsm, median about 2 cfsm)
Application of the above range in yields to the drainage area (0.37 sgmi) for the point of interest results in the following
estimated low -flow discharges:
Annual 7Q10 low -flow discharges =_> from 0.085 to 0.16 cfs (both average and median about 0.12 cfs)
Annual 30Q2 low -flow discharges =_> from 0.18 to 0.34 cfs (both average and median about 0.27 cfs)
Winter 7Q10 low -flow discharges =_> from 0.11 to 0.21 cfs (average about 0.17 cfs, median about 0.18 cfs)

Annual 7Q2 low -flow discharges ==> from 0.14 to 0.26 cfs (average about 0.21 cfs, median about 0.23 cfs)
Average annual discharge discharges ==> from 0.7 to 1.2 cfs (average about 0.85 cfs, median about 0.74 cfs)
Please note:
(1) The estimated flows are provided in units of cubic feet per second (cfs).
(2) The low -flow yields provided above are rounded to 2 significant figures. Estimated low -flow discharges less than 1
cfs are rounded to 2 significant figures. If between 1 and 100 cfs, then rounded to 1 decimal place; if greater than 100,
then rounded to the nearest whole number (zero decimal places).
(3) The information provided in this message is based on a preliminary assessment and considered provisional, subject
to revision pending collection of future data and further analyses.
These provisional streamflow statistics are provided via the DWR USGS Low Flows cooperative agreement between the
USGS and the N.C. Department of Environmental Quality, Division of Water Resources.
Hope this information is helpful.
Thank you.
Curtis Weaver
J. Curtis Weaver, Hydrologist, PE Email: kweaverOusas.aov
USGS South Atlantic Water Science Center Online: httns://www.usas.aov/centers/sa-water
North Carolina - South Carolina - Georgia
3916 Sunset Ridge Road
Raleigh, NC 27607
Phone: [phone] // Fax: [phone]
From: Albertin, Klaus P <[e-mail]>
Sent: Wednesday, March 31, 20219:16 AM
To: [e-mail]
Cc: Albertin, Klaus P <[e-mail]>; Hill, David A <[e-mail]>; [e-mail];
Weaver, John C <[e-mail]>; Montebello, Michael J <[e-mail]>
Subject: [EXTERNAL] Low -flow request approval
This email has been received from outside of DOI - Use caution before clicking on links, opening attachments, or
responding.
Your request has been approved and will be forwarded to USGS. A response from USGS usually takes 7 -10 business
days.
Request Flow Statistic Approval

Request ID: 117
Requestor: Holly Whitmyer
Requestor e-mail:[e-mail]
Requestor Phone: [phone]
Local Government:
Public Water Supply:
Consultant: Dewberry
Contact: Holly Whitmyer
Reason: Permit
River/Stream: Norris Branch
Drainage Area (sq. mi.): 0.37
Latitude: 36.23790
Longitude:-81.66773
Other Information:
Statististics: ["7Q10","7Q10 - Winter","30Q2","Average Annual"]
Approved by: Albertin, Klaus P
4

Attachment B
Of Dewberry
DATE: July 7, 2021
To: Mr. Daniel Gryder (Appalachian State University)
MEMORANDUM
RECEIVED
JUL 19 2021
FROM: Anthony D. Miller, PE NCDEQ/DWR/NPDES
SUBJECT: Appalachian State University Water Treatment Plan — Stormwater Infrastructure Analysis
Message
1.0 Introduction
Appalachian State University (ASU) is submitting a major permit modification request and supporting
information to move the current sludge thickener discharge outfall location. The ASU Water Treatment
Plant (WTP) currently discharges backwash and CIP waste to Norris Branch Reservoir under the
auspices of NPDES Permit NC0044423. The existing permit expired March 31, 2021 and ASU has
applied for but has not yet received a renewed permit. The current permit has been administratively
extended, and as such, ASU is submitting a permit application addendum to request a change in the
discharge outfall location.
The current NPDES discharge outfall is in close proximity to the WTP's intake structure in Norris Branch
Reservoir. ASU desires to move the discharge outfall location downstream of the reservoir into Norris
Branch. The primary driver to move the outfall is to reduce impact from the discharge on the water intake.
A secondary benefit to moving the outfall will be potential improvements to the numerical zinc and copper
limits at the new outfall. ASU, NCDEQ, and Dewberry participated in a conference call on May 4, 2021 to
discuss the potential outfall move. DEQ indicated it was feasible to move the discharge location to Norris
Branch. In addition, DEQ agreed to consider allowing ASU to use existing stormwater infrastructure to
convey the discharge to Norris Branch. The following memo highlights existing conditions, proposed
outfall relocation options, and an evaluation of the existing stormwater system.
2.0 Existing Conditions
Figure 1 attached shows the WTP and the existing stormwater system. The existing stormwater system
consists of a series of storm pipes ranging in sizes from 12" to 24". The existing stormwater system flows
from west to east and outfalls to the northeast of the WTP into the Norris Branch. At the discharge point
to the northeast, there is an existing stormwater structure that dissipates energy at the outfall of the
system.
The stormwater system conveys stormwater generated from overland flow within the WTP. Off -site
stormwater flow is conveyed through a storm system that is located at the southwestern portion of the
WTP. Overland flow to this system originates to the south of the site and then bypasses the site.
Therefore, stormwater from this area was not considered in the evaluation.
The existing sludge thickener that is located at the WTP currently sends its discharge to the north of the
site to Norris Branch Reservoir. The existing reservoir is currently used as a monitoring station and
holding area. The location of the sludge thickener discharge raises concerns due to impact from the
discharge on the water intake. The concentration of copper and zinc in the wastewater at times exceeds
the limits of copper and zinc of 4 pg/L and 63 pg/L, respectively. This is due in part to the current
discharge of the sludge thickener.
ASU WTP STORMWATER INFRASTRUCTURE ANALYSIS 1 OF 3

3.0 Proposed Improvements
Proposed improvements for this project include the installation of a new 6" Ductile Iron sludge thickener
outlet pipe extension. Based on conversations with ASU, two options utilizing the existing treatment plant
processes are proposed for the improvements. See attached Figure 2 for a diagram of the proposed
options.
Option 1: Proposed improvements associated with this option include the installation of approximately 35
LF of 6" Ductile Iron pipe. This option would tie the proposed outlet pipe into a nearby storm structure at
an invert elevation of 3458.17 and utilize the existing stormwater system to discharge into Norris Branch
downstream of the dam. The proposed outfall monitoring point will be located at the end of the new 6"
Ductile Iron pipe. With the invert of 3460.92 at the sludge thickener discharge, the sludge thickener could
dewater approximately 2.75' lower than the existing invert of the 6" outlet pipe. Preliminary probable
construction cost for this option is $15,000.
Option 2: Proposed improvements associated with this option include the installation of approximately
240 LF of 6" Ductile Iron pipe and a new doghouse manhole to be placed on the existing 24" storm pipe
downstream and utilize the existing stormwater system to discharge into Norris Branch downstream of the
dam. The proposed outfall monitoring point will be located at the end of the new 6" Ductile Iron pipe. The
proposed doghouse manhole would be placed on the storm pipe so the invert elevation would be
3451.00. This would allow for the sludge thickener to be drained to an elevation of 3451.00, which is
approximately 2.5' above the bottom of the sludge thickener. Preliminary probable construction cost for
this option is $61,000.
4.0 Stormwater Evaluation
To determine the feasibility of the proposed improvements to the sludge thickener outfall, Dewberry
performed a capacity evaluation of the existing stormwater system. Existing hydrologic conditions were
evaluated based on the Rational Method for the 25-year storm event. Rainfall values for the project area
were determined by utilizing NOAA Atlas 14 for precipitation intensity. A weighted Rational Method Runoff
Coefficient (c-value) was determined for the drainage area(s) using the existing land use. Time of
concentration values were set to 5 minutes for the catchment(s) as most of the stormwater flow comes
from paved surfaces and ultimately is channelized within storm conveyances. See Figure 3 attached for a
drainage area map.
Hydraulic computer modeling for evaluating the existing storm system was performed using the AutoCAD
Express software program. The modeling software determined the hydrograph for the existing system
based on the drainage area, c-value, and time of concentration. In addition to the flow generated by
rainfall through the stormwater system, the evaluation also included the discharge rate from the sludge
thickener of 400 GPM (0.89 cfs). Using the 25-year outflow from the hydrograph and added flow from the
sludge thickener pipe capacity was determined for the stormwater system. See the calculation reports at
the back of this memo.
Option 1 will discharge to an existing 18" storm drain located near the sludge thickener. Based on the flow
rate resulting from the 25-year storm event and the added flow from the sludge thickener, the existing 18"
pipe is at 46% capacity and the downstream 24" pipe is at 23% capacity.
Option 2 will discharge to an existing 24" storm drain located near the existing clearwell. Based on the
flow rate resulting from the 25-year storm event and the added flow from the sludge thickener, the
existing 24" pipe is at 23% capacity.
V. DewberryAs, WTP STORMWATER INFRASTRUCTURE ANALYSIS 2 OF 3

5.0 Conclusion
Based on the proposed improvements associated with project and the evaluation of the existing
stormwater system, the existing storm drainage conveyance system has the capacity to carry the
additional 400 GPM discharge from the sludge thickener.
Attachments
1. Figure 1: Existing Conditions
2. Figure 2: Proposed Improvements
3. Figure 3: Drainage Area Map
4.Option 1 Stormwater Evaluation
5.Option 2 Stormwater Evaluation
6.Option 1 Preliminary Opinion of Probable Construction Cost
7.Option 2 Preliminary Opinion of Probable Construction Cost
:02
;,: Dewberry
ASU WTP STORMWATER INFRASTRUCTURE ANALYSIS 3 OF 3

E
EXISTING RESERVOIR

Hydrology Report
Hydraflow Express Extension for Autodesk@ AutoCADO Civil 3D® by Autodesk, Inc.
Drainage Area - Option
1
Hydrograph type
= Rational
Storm frequency (yrs)
= 25
Drainage area (ac)
= 1.100
Rainfall Inten (in/hr)
= 8.403
OF Curve
= ASU.IDF
Q (cfs)
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0 00
Thursday, Jul 8 2021
Peak discharge (cfs)
Time interval (min) = 1
Runoff coeff. (C) = 0.7
Tc by User (min) = 5
Rec limb factor = 1.00
Hydrograph Volume = 1,941 (cuft); 0.045 (acft)
Runoff Hydrograph
25-yr frequency
0 5 10
Time (min)
Runoff Hyd - Qp = 6.47 (cfs)

I
Channel Report
Hydraflow Express Extension for Autodesk@ AutoCADO Civil 3D® by Autodesk, Inc.
Existing 18_in
Outfall
Circular
Diameter (ft)
= 2.00
Invert Elev (ft)
= 3434.18
Slope (%)
= 1.62
N-Value
= 0.013
Calculations
Compute by:
Known Q
Known Q (cfs)
= 7.36
Friday, Jul 9 2021
Highlighted
Depth (ft)
= 0.69
Q (cfs)
= 7.36
Area (sqft)
= 0.97
Velocity (ft/s)
= 7.60
Wetted Perim (ft)
= 2.52
Crit Depth, Yc (ft)
= 0.96
Top Width (ft)
= 1.90
EGL (ft)
= 1.59
Flow through pipe is flow generated
from the 25-year storm in addition to
the 400 gpm (0.89 cfs)
flow from the
sludge basin
Elev (ft) Section
3437.00
3436.50
3436.00 /000�
3435.50
3435.00
3434.50
3434.00
Id'11 Rn
0
2
Reach (ft)
3 4

Hydrology Report
Hydraflow Express Extension for AutodeskO AutoCADO Civil 3DO by Autodesk, Inc.
Drainage Area - Option 2
Hydrograph type
= Rational
Storm frequency (yrs)
= 25
Drainage area (ac)
= 3.490
Rainfall Inten (in/hr)
= 8.403
OF Curve
= ASU.IDF
Q (cfs)
15.00
1 12.00
• 11
3.00
rrAWAT
Thursday, Jul 8 2021
Peak discharge (cfs)
Time interval (min)
= 1
Runoff coeff. (C)
= 0.49
Tc by User (min)
= 5
Rec limb factor
= 1.00
Runoff Hydrograph
25-yr frequency
Hydrograph Volume = 4,311 (cuft); 0.099 (acft)
Q (cfs)
15.00
12.00
9.00
6.00
3.00
000
0 5 10
Time (min)
Runoff Hyd - Qp = 14.37 (cfs)

Channel Report
Hydraflow Express Extension for Autodesk@ AutoCAD® Civil 3DO by Autodesk, Inc.
Existing 24_in
Outfall
Circular
Diameter (ft)
= 2.00
Invert Elev (ft)
= 3434.18
Slope (%)
= 32.71
N-Value
= 0.013
Calculations
Compute by:
Known Q
Known Q (cfs)
= 15.26
Thursday, Jul 8 2021
Highlighted
Depth (ft)
= 0.46
Q (cfs)
Area (sqft)
= 0.55
Velocity (ft/s)
= 27.62
Wetted Perim (ft)
= 2.01
Crit Depth, Yc (ft)
= 1.41
Top Width (ft)
= 1.69
EGL (ft)
= 12.32
Flow through pipe is flow generated
from the 25-year storm in addition to
the 400 gpm (0.89 cfs) flow from the
sludge basin
Elev (ft) Section
3437.00
3436.50
3436.00
3435.50
3435.00
3434.50
3434.00
3433.50
0
1
2
Reach (ft)
3 4

Preliminarf
Opinion of Probable Construction Cost Dewberry
ASU Skidge Basin Outfail Feasibility D•wh•m En9ieeer. ]or.
50140792 TRADE SITE 9300 Nam C•.n•n P k.t.y . Sit.
Preliminary Cost Estimate DATE. 07/07/21 Ch-lon s NC 2926
PROJECT NO.
PHASE:
LINE ITEM
MATERIALS
LABOR
EQUIPMENT
TOTAL
NO.
ITEM
NO. UNITS $/UNIT
NO. UNITS I $/UNIT
NO. PNITJ $/UNIT
COST
MISC. Items
I LS I $5,000.00
Mobilization
$5,000.00
DemoYtion/ESC
.
Demolition of EAsting Asphalt
12
SY $25.00
LF $4.15
$300.00
Temporary Silt Fence
35
$145.25
Stone Outlets
1
EA
$250.00
$250.00
Temporary ing and Mulching
0.01
AC
$4,000.00
$40.00
Inlet Protection
1
EA
$500.00
_.
$5D0•G0
Erosion and Sediment Control Maintenance
1
MO
$1,500.00
$1,500.00
Site Work
8" Aggregate Base Course
12
SY
$5.50
_
$66•00
Asphalt Surface Course
12
SY
$25.00
_ _ $300.00
Permanent Seeding
0.01
AC
$4,500.00
$45.00
Grading and Stormwater
_ $1,000.00
$875.00
$1,575.00
UOtitlss
Connect to Ewsting Structure
1
EA
$1,000.00
_ _ _
Pipe Excavation
35
LF
$25.00
DIP
35
LF
$45.001
SUB -TOTAL
Construction Contingency
SUB -TOTAL
TOTAL
ESTIMATE
$11,S%.25
_ 2443.88
$2,443.88
$14.040.13
NOTES:
..__
I _ _

Preliminarr
Opinion of Probable Construction Cost
ASU Sludge Basin Outfall Feasibility _L
50140792 -
Preliminary Cost Estimate
_ Dewberry
I _ uowher,y Eoxi— . lor.
SITE 93M HuTis Corns. Parkway - Suite 22
07/07/21 Ch-1 tte, NC 2826
PROJECT NO.:
TRADE:
PHASE:
DATE:
LINE ITEM
MATERIALS
LABOR
EQUIPMENT
TOTAL
NO.
ITEM
NO.
UNITS $/UNIT
NO. UNITS $/UNIT
NO.
PNITA
$/UNIT
COST
Misc. Items
Mobilization
1
LS $10,000.00
_
$10,000.00
Demolltlon/ESC
Site Clearing & Grubbing
0.02
AC $6,000.00
LS $9,000.00
$120.00
Tree Removal
1
$9.000.00
_
Flagging of Clearing Limits
65
LF
$1.25
$8125
Temporary Silt Fence
250
LF
$4.15
$1,037.50
Stone Outlets
2
EA
$250.00
$500.00
Temporary Seeding and Mulching
0.02
AC
$4.000.001
$80.00
Inlet Protection
3
EA
$W.00
$1,500.00
Erosion and Sediment Control Maintenance
3
MO
$1.500.00
$4,500.00
Site Work
Permanent Seeding
0.02
AC
$4,SW.00
$90.00
_
Utilities
Connect to Proposed Manhole
i
EA
$1.000.00
$1,000.00
-�
Pipe Excavation
245
LF
$25.00
$6,125.00
8* OF
245
LF
$45.00
$11,025.00
Doghouse Manhole
1
EA
$7,5W.00
$7,500.00
SUB -TOTAL
$52,558.75
Construction Ciontingency
$8,072.C3
30.0%1
SUB -TOTAL
$8,072.63
TOTAL
60 631.38
1000

Attachment C
1 Dewberry
DATE: July 7, 2021
MEMOR���¢�j�1D
CIVC
JUL 19 2021
TO: Mr. Daniel Gryder (Appalachian State University)
FROM: Ryan P. Ames, PE (Dewberry) NCDEUDWRINPDES
SUBJECT: Appalachian State University Water Treatment Plant — Metals Treatment Alternatives Analysis
Message
Appalachian State University (ASU) operates a water treatment plant (WTP) that draws water from Norris
Branch Reservoir. Currently, wastewater generated by the water treatment process is discharged back to
Norris Branch reservoir under NPDES permit NC0044423. The monthly average copper and zinc limits,
which became effective on January 1, 2021, are 4 pg/L and 63 pg/L, respectively. The concentration of
copper and zinc in the wastewater at times exceeds these limits.
ASU is in the process of requesting a major permit modification to change the location of the NPDES
discharge to a point in Norris Branch downstream of the reservoir. The primary driver to move the outfall
is to reduce impact from the discharge on the water intake. A secondary benefit to moving the outfall will
be that the 7Q10 flow will allow for higher discharge limits for copper and zinc. As part of that permit
application, the North Carolina Department of Environmental Quality (NCDEQ) has requested evaluation
of two alternatives for treatment of copper and zinc to ensure that moving the outfall location is the most
technologically and economically feasible.
Reverse osmosis and ion exchange were evaluated as potential alternatives for removal of copper and
zinc from the wastewater prior to discharge to the Norris Branch Reservoir. The following sections
describe expected effectiveness, preliminary sizing, order of magnitude cost and qualitative comparison
of advantages and disadvantages of each treatment alternative. An evaluation of the cost to move the
discharge outfall is provided under a separate memo.
Ion Exchange
Ion exchange (IX) is a process in which wastewater flows through a bed of specialized media, or resin,
that is designed to adsorb ions that have affinity for active sites on the media. When an ion, such as
copper, is adsorbed onto an active site, it displaces an ion that has a lower affinity for that active site,
such as hydrogen or sodium. Resins for IX processes can be engineered to have greater affinity for
target contaminants, thereby selectively removing those contaminants from the waste stream.
Figure 1 shows a block flow diagram of the conceptual design of an IX treatment system for removal of
copper and zinc from the WTP wastewater. Dewberry proposes that the normal wastewater discharge
would be directed to a 50,000 gallon surge tank over the normal 2 hour discharge period from the existing
sludge thickener. The wastewater would then be pumped to the IX system at a lower rate over
approximately 6 hours per discharge day. At the average discharge volume of approximately 18,000
gallons per day (gpd) this equates to a process flow rate of approximately 50 gpm. This approach helps
to reduce the size and cost of the IX system.
Wastewater would be pumped from the 50,000 gallon surge tank through a cloth media filter. The filter
would reduce solids and turbidity prior to the IX resin beds to prevent fouling and degradation of the
media. Backwash water from the cloth media filter will be directed to the existing sludge thickener and
solids from the backwash water would be disposed with other solids from the water treatment process.
The cloth media filter would discharge to a small tank where sulfuric acid would be added to reduce the
pH to approximately 4 standard pH units (SU) to ensure that copper is in an ionic form that can be
removed by the IX resin. The pH adjusted wastewater would then be pumped through the IX resin beds.
ASU METALS TREATMENT ALTS. ANALYSIS 1 OF 3

Mr. Daniel Gryder
July 7, 2021
For conceptual design purposes, we have assumed that the IX system would be configured in two parallel
trains, and that each train would utilize one vessel of copper selective resin and one vessel of zinc
selective resin. It may be feasible to find a single resin that will efficiently remove both copper and zinc.
Following the IX system, a caustic dosing system will adjust the pH of the treated wastewater to meet pH
limits in the discharge permit.
The IX system would need to be installed in a building. For conceptual design purposes a new 45 foot x
30 foot process building is proposed.
Dewberry developed a conceptual opinion of cost based on the IX treatment system described above.
The approximate capital cost of this system would be on the order of $2.1 million. The opinion of cost is
summarized in Table 1.
Aside from the cost of the media, the IX system would have a low cost of operation. Power cost would be
low because the power demands for the system are limited to low pressure transfer pumps, chemical feed
pumps and mixers. Labor requirements would also be relatively low, limited to periodic filling of pH
adjustment chemicals, monitoring of pressure loss across the resin bed, and sampling to monitor system
performance. Some IX systems have a significant chemical cost for regeneration of the IX media, and as
a result, also have a significant regeneration waste stream that must be managed and disposed. The
media proposed for this system is typically not regenerated, however, this means that the media must be
replaced approximately annually. The cost of annual media replacement would likely be between
$50,000 to $100,000.
Installation of an IX system is not recommended based on this analysis, however, if it is deemed the most
feasible option, pilot testing of IX is recommended prior to detailed design to evaluate resin selection,
resin performance, bed life, relative costs of regeneration versus replacement, and pH adjustment
chemicals.
Reverse Osmosis
Reverse osmosis (RO) is a membrane process that represents a physical barrier for removal of many
contaminants at the molecular level. The water to be treated is pumped through the membrane at high
pressure (125 to 1,000 psi) and contaminants, such as copper and zinc are retained by the membrane in
a concentrated waste stream. To minimize the volume of this concentrated waste stream, a three stage
RO system is proposed. In a multistage RO system, the retained concentrate from one RO system is
directed to the influent of another RO system. Each stage can typically achieve 50% to 75% recovery of
treated water from the wastewater stream.
Figure 2 shows a block flow diagram of the conceptual design of a RO treatment system for removal of
copper and zinc from the WTP wastewater. Dewberry proposes that the normal wastewater discharge
would be directed to a 50,000 gallon surge tank over the normal 2 hour discharge period from the existing
sludge thickener. The wastewater would then be pumped to the RO system at a lower rate over
approximately 6 hours per discharge day. At the average discharge volume of approximately 18,000
gallons per day (gpd) this equates to a process flow rate of approximately 50 gpm. This approach helps
to reduce the size and cost of the RO system.
Wastewater would be pumped from the 50,000 gallon surge tank to a microfilter system. A microfilter will
be installed upstream of the RO system to remove particulates to protect the RO membranes. The micro
filter will discharge into a small tank that will serve as a supply tank for backwashing the microfilter.
Backwash water will be directed to the existing sludge thickener and solids from the backwash water
would be disposed with other solids from the water treatment process.
_ Dewberry ASU METALS TREATMENT ALTS. ANALYSIS 2 OF 3

Mr. Daniel Gryder
July 7, 2021
A high-pressure pump will convey pretreated wastewater from the backwash supply tank to the three
stage RO system. Permeate will be directed to the outfall for final disposal. The concentrated RO reject
stream will be accumulated in a holding tank for periodic disposal off site.
The microfilter and the RO membrane can be fouled by mineral deposits from the wastewater or by
biological growth. This fouling must be cleaned periodically to maintain the performance of the microfilter
and RO systems. A clean -in -place (CIP) system will be required to remove fouling. The CIP system will
pump an acidic solution through the membranes to remove mineral fouling and a sodium hypochlorite
solution through the membranes to remove biofouling. A chemical feed system will also be included to
add anti-scalant chemical upstream of the RO system to limit mineral fouling.
The RO system would need to be installed in a building. For conceptual design purposes a new 45 foot x
30 foot process building is proposed.
Dewberry developed a conceptual opinion of cost based on the RO treatment system described above.
The approximate capital cost of this system would be on the order of $4.2 million, or approximately two
times the cost of the IX system described above. The opinion of cost is summarized in Table 2.
The cost of operation of the RO system is likely to be greater than the cost of operation of the IX system.
The power cost for the RO system is expected to be higher due to the power required to operate the high
pressure pumps that feed the RO process. The difference in chemical costs is difficult to evaluate
because the RO system will utilize chemicals for the periodic CIP, but may not require regular chemical
dosing for pH adjustment. Labor requirements would also likely be similar between the RO and the IX
systems due to similar activities such as filling of CIP chemicals, monitoring of pressure loss across filters,
and sampling to monitor system performance. The RO system will have a significant operational cost
associated with disposal of the concentrate stream. Depending on membrane performance, the
concentrate waste stream could range from 5,000 to 50,000 gallons per month. The RO membranes
would have a service life of approximately 3 years and replacement cost would be approximately
$20,000.
Installation of an RO system is not recommended based on this analysis, however, if it is deemed the
most feasible option, pilot testing of RO is recommended prior to detailed design to evaluate membrane
performance, volume of the reject stream, potential for fouling, and associated chemical requirements.
Attachments
Figure 1: Ion Exchange Block Flow Diagram
Figure 2: Reverse Osmosis Block Flow Diagram
Table 1: Opinion of Conceptual Capital Cost — Ion Exchange
Table 2: Opinion of Conceptual Capital Cost — Reverse Osmosis
Dewberry ASU METALS TREATMENT ALTS. ANALYSIS 3 OF 3

EXISITING
SLUDGE
THICKENER
50,000 GALLON
COVERED
SURGE TANK
SOLIDS TO
OFFSITE
DISPOSAL
BACKWASH
BACKWASH
WATER
SUPPLY
CLOTH MEDIA FILTER
SULFURIC
ACID
Y
LEGEND

BACKWASH
EXI,
SLL
THIC
SOL
OF
DIS
LEGEINU

Table 1- Preliminary Opinion of Probable Construction Cost 49 Dewberry
Ion Exchange ASU Metals Treatment Alternative Analysis
Dewberry Engineers Inc.
PROJECT NO.:
50140792
TRADE: SITE 9300 Harris Corners
Parkway - Suite 220
PHASE:
Preliminary Cost Estimate
DATE: 7/7/2021
Charlotte, NC 28269
Item
Description
Unit gty Unit Cost
Total
1.0 Equipment
1
50,000 gallon batch feed tank
EA 1 $ 75,000
$ 75,000
2
Pre -filter feed pump - 50 gpm
EA 1 $ 5,000
$ 5,000
3
Pre -Filter - Disk Filter
EA 1 $ 125,000
$ 125,000
4
Ion Exchange feed pump
EA 1 $ 5,000
$ 5,000
5
pH adjustment system - acid
EA 1 $ 18,000
$ 18,000
6
Ion Exchange System - 4 x 30 CF columns
EA 1 $ 100,000
$ 100,000
7
ph adjustment system - base
EA 1 $ 18,000
$ 18,000
TOTAL PROCESS EQUIPMENT COST
$ 346,000
2.0 Auxiliary
Items (Installed)
8
45' x 30' Building and appurtenances
LS 1 $ 270,000
$ 270,000
TOTAL AUXILIARY ITEMS INSTALLED COST
$ 270,000
3.0 Project Capital Costs
TOTAL PROCESS EQUIPMENT COST (TPEC)
$ 346,000
9
Installation, Piping, Electrical, Instrumentation and Controls
$ 500,000
TOTAL INSTALLED PROCESS EQUIPMENT COST (TIPEC)
$ 846,000
10
Installed Auxiliary Items Cost (Item 2.0)
$ 270,000
Sub -Total
SUM TIPEC+ITEM 15
$ 1,116,000
11
Contractor Overhead and Profit
10%
$ 110,000
12
Contractor General Conditions
Month 6 $ 12,500
$ 75,000
Sub -Total
$ 1,301,000
Contingency
40%
$ 520,000
FIXED CAPITAL COST ESTIMATE:
$ 1,821,000
13
Engineering and Permitting
15.0%
$ 273,000
TOTAL ESTIMATED CAPITAL COST (TCC):
$ 2,100,000
NOTES AND ASSUMPTIONS
1 System is sized for 50 gpm and will typically operate 6 hours per day.
2 Assumes the project is tax exempt
3 Assumes minimum soil bearing capacity of 2000 psf; estimate does not include piles or other special foundations.
4 Assumes adequate primary electrical service exists within 100 feet of the site, or that utility will
provide if new service is required.
5 Does not include costs for auxilliary power source, i.e. generator.
6 Electrical & controls allowance is intended to cover MCCs, wiring & conduit and basic controls.
7 Significant dewatering will not be required for construction of building and tank foundations.

Table 2- Preliminary Opinion of Probable Construction Cost 19 Dewberry
Reverse Osmosis ASU Metals Treatment Alternative Analysis
Dewberry Engineers Inc.
PROJECT NO.: 50140792
TRADE: SITE 9300 Harris Corners Parkway - Suite 220
PHASE: Preliminary Cost Estimate
DATE: 7/7/2021 Charlotte, NC 28269
Item Description
Unit gty Unit Cost
Total
1.0 Eaulpment
1 50,000 gallon batch feed tank
EA 1 $ 75,000 $
75,000
2 Micro Filter, 3-State Reverse Osmosis System, pumps, CIP system
EA 1 $ 1,454,352 $
1,454,400
TOTAL PROCESS EQUIPMENT COST $
1,529,400
2.0 Auxiliary Items Ilnstalledl
3 45' x 30' Building and appurtenances
LS 1 $ 270,000 $
270,000
TOTAL AUXILIARY ITEMS INSTALLED COST $
270,000
3.0 Project Capital Costs
TOTAL PROCESS EQUIPMENT COST (TPEC) $
1,529,400
4 Installation, Piping, Electrical, Instrumentation and Controls
$
500,000
TOTAL INSTALLED PROCESS EQUIPMENT COST (TIPEC) $
2,029,000
5 Installed Auxiliary Items Cost (Item 2.0)
$
270,000
Sub -Total
Sum TIPEC+ITEM 15 $
2,299,000
6 Contractor Overhead and Profit
10% $
230,000
7 Contractor General Conditions
Month 6 $ 12,500 $
75,000
Sub -Total
$
2,604,000
Contingency
40% $
1,042,000
FIXED CAPITAL COST ESTIMATE: $
3,646,000
8 Engineering and Permitting
15.0% $
547,000
TOTAL ESTIMATED CAPITAL COST (TCC): $
4,200,000
NOTES AND ASSUMPTIONS
1 System is sized for 50 gpm and will typically operate 6 hours per day.
2 Assumes the project is tax exempt
3 Assumes minimum soil bearing capacity of 2000 psf; estimate does not include piles or other special foundations.
4 Assumes adequate primary electrical service exists within 100 feet of the site, or that utility will
provide if new service is required.
5 Does not include costs for auxilliary power source, i.e. generator.
6 Electrical & controls allowance is intended to cover MCCs, wiring & conduit and basic controls.
7 Significant dewatering will not be required for construction of building and tank foundations.